The worlds demand for electric power, heat and hydrogen will in the foreseeable future be based on gaseous, liquid or solid fossil fuels. Thus international concerns over global warming would be increasingly focusing on carbon capture and storage (CCS). Development of environmentally friendly, cost and energy efficient technologies, including handling of the CCS-issue, is therefore inevitable.
One of the major challenges in this connection is the recovery and upgrading of extra heavy oil and bitumen. Because of a simultaneous global increase in the fossil energy demand and decrease in the conventional resources, the oil industry will turn to unconventional resources. It should in this connection be mentioned that there are more than 4000 billion barrels of Extra Heavy Oil (EHO) and Bitumen accumulated world wide. The recovery and upgrading of these resources, for example from tar-sands, are very energy intensive processes with strong impact on the environment.
In the tar-sand industry natural gas is to day primarily used to generate steam (for example for SAGD (Steam assisted gravity drainage)), electric power and to produce hydrogen for upgrading processes.
Concerns over long-term natural gas cost and supply have however motivated operators to consider gasification based energy production for future projects. Commercial bitumen upgrading processes generate high-sulphur pet-coke asphaltene by-products, which are currently stock-piled. These opportunity fuels could (together with coal and/or an untreated portion of the bitumen, if necessary) be gasified to produce hydrogen, electric power and steam, thus potentially eliminating the need for valuable natural gas.
The first of such gasification based systems is currently in an advanced stage of construction in Alberta, Canada. The Long Lake project owned by Opti-Nexen Canada, Inc. is a fully integrated bitumen extraction and upgrading facility fuelled by gasification of asphaltene residue. (G. Ordorica-Garcia et. al, Energy Procedia 1 (2009) 3977-3984: CO2 Capture Retrofit Options for a Gasification-based Integrated Bitumen Extraction and Upgrading Facility). The gasification units provide hydrogen required for upgrading and syngas fuel for power and steam production in a co-generation plant, resulting in almost fully energy self-sufficient operations.
However, use of natural gas and/or syngas results in release of substantial amounts of CO2 into the atmosphere, contributing to global warming.
To day, application of CCS-technology, within the oil-sand industry, is primarily targeted towards hydrogen production- and electrical power plants, as they are the largest point sources of CO2. Future integrated gasification based plants (production of; syngas, steam, electric power and hydrogen (for upgrading)) will also have to meet the CCS-challenge. If CO2-capture, in such cases, is based on to-days available technologies, this will have a substantial impact on capital and operating costs, as well as plant performance (particularly if retrofitting is needed).).
A method and apparatus for “Hydrogen Production From Carbonaceous Material”, has been patented by Lackner et al, WO 01/42132 A1. This apparatus performs; Gasification of coal by hydrogenation in a gasification vessel. This process stage is followed by hydrogen production from methane and water that is driven using a calcium oxide carbonation reaction in a carbonation vessel. Such a process is often referred to as; Hydrogen production by sorption enhanced steam methane reforming (SE-SMR). In the gasification step (Lackner et al.) coal (or syngas) is hydrogenated with hydrogen to produce a gaseous reaction product consisting primarily of methane. This gaseous reaction product is conveyed to the carbonation vessel, where it is reacted with water and calcium oxide to produce hydrogen and solid calcium carbonate and to remove carbon dioxide from the product gas stream.
The Lackner et al.-process provides no extra heat for example for SAGD. Thus the process lacks versatility desirable for a lot of interesting applications. Furthermore all the CO2 of the process system is captured in a SE-SMR-process. This may not be cost effective in applications where large amounts of external heat combined with the necessary amounts of hydrogen and electricity are needed, for example in the tar sand industry.
The publication WO 2004/025767 (Vik et al.) discloses a plant for the production of electricity from a hydrocarbon containing flow. According to one embodiment a SOFC is used for producing the electricity. The process involves reforming of the fuel in order to produce hydrogen before separating it from the other components to use pure hydrogen as the feed to the fuel cell. CO2 produced during reforming may be captured for subsequent use or storage. The process of Vik et al. is targeted towards applications where excess heat is not needed, and where high efficiency for the co-production of electricity and hydrogen only is the primary object.
Hence new technology, preferably a game change, focused on energy optimization, CO2-capure and sub-surface storage or use (f. ex. EOR) is needed.